Simple synthesis of alkyl derivatives of tetrathienoacene and their application in organic field-effect transistors

Abstract

Friedel-Crafts acylation of tetrathienoacene (TTA) following by reduction reaction resulting in various octyl-substituted TTA derivatives is described for the first time. Varying conditions of the acylation reaction allowed controlling the...

Uncovered Effects of thieno[2,3-b]thiophene Substructure in a Tetrathienoacene Backbone: Reorganization Energy and Intermolecular Interaction

“…Organic field-effect transistors (OFETs) have attracted considerable attention in the last two decades, and their performance has seen significant improvement. , Today, they are regarded as a potential technology for the realization of lightweight and flexible electronics. − On the other hand, it is necessary to improve strategies for the development of superior organic semiconductors. − Acene and heteroacenes are prototypical organic semiconductors for p-channel OFET applications, , and among them, thiophene-containing fused aromatic compounds, often called thienoacenes, have been actively investigated . Tetrathienoacene (thieno­[2″,3″:4′,5′]­thieno­[2′,3′- d ]­thieno­[3,2- b ]­thiophene or 4TA, Figure ), first synthesized by Mazaki and Kobayashi, , is a prime example of such thienoacenes and has been frequently utilized as a building block for organic semiconductors in the last two decades. ,− 4TA has the following features: (i) a linear and rigid molecular structure with four sulfur atoms; (ii) an alternating conjugation path through all four thiophene rings; and (iii) an isoelectronic structure with chrysene. The first two features are rooted in its molecular structure, which consists of four thiophene rings fused as the thieno­[3,2- b ]­thiophene substructure.…”

Dragon-Boat-Type Heptathienoacenes: Synthesis, Structures, and Their Applications in OFETs

“…All of the fabricated devices exhibited typical p-channel characteristics, and DBHT-5 -based OFET devices showed the highest hole mobility up to 1.15 cm 2 V –1 s –1 (average mobility of 0.91 cm 2 V –1 s –1 ) with the threshold voltage of 0 V and the on/off ratio over 10 6 on the OTS-treated Si/SiO 2 substrate (Figure d). Compared with the thienoacenes and derivatives based on alkylated, arylated, and phenylalkyl substitution − (Figure ), the OFET performance of DBHT s is much higher. The DBHT-5 -based device showed high cyclic stability in the test process; its transfer curve changed very little when the device underwent repeated opening 20 times within 1 h of continuous test (Figure e).…”

“…To date, there are limited reports on [ n ]­thienoacenes ( n = 3–6) and their derivatives in applications of organic semiconductors. The alkylated and arylated derivatives of [3]­thienoacene ( DTT ) and [4]­thienoacene ( TTA ) showed hole mobilities of 0.04 and 0.13 cm 2 V –1 s –1 , respectively (Figure a,b). With increasing the thiophene unit, however, [5]­thienoacene ( PTA ) without substituents gave a low mobility of 0.045 cm 2 V –1 s –1 (Figure c), while [6]­thienoacene ( HTA ) exhibited a little higher mobility of 0.06 cm 2 V –1 s –1 (Figure e) using thin film devices fabricated on OTS-treated SiO 2 /Si substrates.…”